Swing frame grinder



April 9, 1946. c. E. Hm: 2,398,308

SWING FRAME GRINDER Filed Dist. 24, 1944 v $1 I I 6,3!

' 24 I," V I v i I I l/em or 55 1w 2AM;

Patented Apr. 9, 1946 NSWINGFBAME GRINlJER a eases El me, 'Philadelphia,- Pa., Albert 1P. de Sanno, Jr.,

assignor to Phoenixville, Pa.

7 Application October 24, lsiaseria'l No. 560,137 Claims. (Cl. 51-99) QMy present invention relates to swing frame grinders and more particularly to a swing frame grinding machine having ,a releaseof the handle bars to downward movement when, the bars are subjected to unduly highrdown-pressure and in part the invention maybe considered a develop ment .of the subject matterdisclosed and claimed in myo; S,..;l?atent,Nq.2,290,611, granted October 12, 1940,; and entitled Swing l-frame grinder; v w m; ob'iect orthjinverition is tornechanically limitfi the downpressureftransmissible by an operator of aswing 'frame grinding machine to the rinding wheel and piece ofwork being ground,

thereby preventing an operator from] applyingwheel pressures dangerously or undesirably high. A further purpose is to reduce Wheel'hazard, maintain. continuing j cutting' efiectiveness and wheel strength, lengthen wheel life and to reduce the over-all cost ofswing frame grinding operations.,, i l,

;A further object is, tohinge the handle bars of aswing frame grinderfto the protectionhood of the' wheel unit and to resiliently supportlthe handle bars in their position of use except when subjectedltp [an abnormally high dow n pressure bythe operator. m A furtherjobjectfi's to have the handle bars sink out oftheir position of use when subjected port withoutthe otherhaving particular advanta'gesfthough normally less advantageous than the cooperating use of both.

A8 to the train of evils intended to becured through the present invention, the application by the grinding operatorsof excessive pressure upon the handle barsihas increased operating stresses and strains within'wheels and power consumption in driving themand more serious than this has resulted in unduly heating the work and, the wheels .j.,, f a Th'eundue heating of the wheels and work has caused the wheel faces to glaze with metal from the work and has also weakened the wheels, lessened the, intrinsic strength of the bondingmaterial holding together their abrasive grains.

to abnormally high down pressure, thereby pre venting grinding 'with undul high pressures upon the handle bars. f A further objectis to materially lessensh'cck and vibration, that between the wheel and work and that transmitted through the handle bars to the operator, using resilience in the support of thehandle bars from the hood and preferably also resilience in the support of the hood from the frame.

.A further object is to provide the handle bars with a narrow range of upward and downward movement under a corresponding range of rising and falling down-pressures applied by thebperator and with a release-of a resilient support when the down-pressure applied to the handle bars rises toa selected limit.

A further object is to provide the hinged andle bars" with two resilient supports against downward. movement from their position of'use, one support with complete release at the end 'of a short downward movement of the' handle bars and the other support with" continuing retraction throughout the downward'swing of the handle bars. V A further object is optionally to omit one or other of the two supports, the use of either sup- The weakening of the wheels from overheating and the increased stresses and strains within the wheels from too high pressures has caused wheels to fly apart in service, making the operation, particularly of heavy duty wheels, extremely hazardous.

And the glazing of the cutting faces has made the cutting ineffective, making it necessary, to dress'wheel faces when without such unnecessary glazing the dressing operation with the resultant loss of wheel material and of'the eflective use of the wheel could have been avoided.

Further objects will appear in the specification and in the claims.

I have elected to illustrate two onl of the different forms of my invention, illustrating forms, however, that practical and eiiicient in operation and which 'well illustrate the principles involved.

The figures-of the drawing are intended to be conventional and to brin out more clearly the principles involved are in great measure diagrammatic.

Figures 1 and 2 are side'elevations of somewhatdiiferent embodiments of the invention, with the views intended to be alike except with respect to a distinguishing feature.

7 Figure 3 is a bottom plan fragment. Like numerals refer to like parts in all figures. "Describing in illustration and not in limitation and referring to the drawing:

inner end of the operating handle or handle bars Ii welded or rigidly fastened to the opposite side of the hood, as at l9.

To both limit pressure transmissible by the operator through the handle bars and to shield the operator from the hood vibration, I weld or other wise fasten conventional handle bars to opposite sides of a rocker 2i, pivoting the rocker at 22 in opposing lugs 23 of the hood 1.

The rocker is provided with an upward arm 24 and an opposing upward arm 25 of the hood carries springs 26 and 21 that engage the arm 24 and normally retract it'against a stop lug 28 from the hood. l

The spring 26 is a tension spring, preferably a spring of pre-set tension, that is, a spring with the successive turns of the spring in contact;

pressing together until the initial or pre-set tension is overcome when the rocker begins to be pulled away from the high position at which it presents the handle bars 20 in positionifor convenient use by the operator.

The spring 21 is a flat spring with a latching head having inner and outer reversely sloping surfaces 29 and 3!] to engage the top of the rocker arm 24.

The spring ing washers 3| 21 is held to its duty between opposand 32 by a stud 33 into the flat top of the arm 25. The washers are slotted at 34 in direction of the spring length to permit adjustment of the spring strength by shifting the washers or either washer.

In normal high position of the rocker and handle bars the spring 21 presents its bevel surface 29 against the top of the rocker, resiliently resisting any downward deflection of the handle bars until any such deflection carries the top of the rocker beyond the slope 29.

When the handle bars are raised from a low position to their high position of normal operation, the outer sloping surface slides along the top of the rocker arm, lifting the spring 21 for its latching engagement between the surface 29 and the top of the rocker.

When an operator applies excessive downpressure to the handle bars, moving them downward from their high position, they are given a momentary additional urge downward by the fiat spring 21 during its engagement at the surface 3!) with the top of the arm 24.

The spring 21 is intended to comprise any suitable spring latch between the rocker handle bars in their high position and the hood, holding the handle bars in their high position for a short up-and-down range of movement of the bars, releasing the bars when the limit of short downwardmovement is exceeded (because of excessive down-pressure applied by an operator), and letting the bars then drop except as theymay be desirably under a retracting upward support of the spring 26.

The spring 26 is intended to comprise any suitable spring connection between the rocker handle bars and the hood providing the bars with resilient upward support throughout a range of up-and-down movement of the bars.

The springs 26 and 21 are intended to be selected and placed for their combined strength to hold the rocker handle bars in their high position against normal operating down pressure upon the bars and to permit the handle bars to move downward if an operator applies to them excessive down pressure.

Some of 'the'advantage's may be obtained by the use of either spring without the other and when this is done the strength and placement of the used spring should hold the handle bars in their high position against normal operating down pressure uponthe bars. and permit the handle bars to move downward under excessive pressure upon the bars.

An important object of the springs 25 and 21 where both are used, or of either spring used without the other, is to absorb or cushion hood vibration otherwise transmitted through the handle bars to the operator.

When the hood has given rigid support to the handle bars, in accord with frequent practice of the prior art, the heavy vibration during heavy duty. service, from the hood through the handles to thoperator, has been'a seriouscharacteristic or this type of grinder, both in the effects on the operatorfromthe heavy'shakin'g given him during service and in the effects on the wheel in that the shocks on the operatortran'smit back to the wheel.

When the hood has carried the wheel unit and handle bars and been itself carried by the frame with a rigid direct connection between the frame and hood, as by welding the hood at 6 to th end of the frame, in accord with frequent practice of the prior art, the heavy vibration transmitted from the hood to the frame and through the frame to the driving mechanism has also been a serious characteristic of this typegrinder, subjecting the driving mechanism to heavy shaking with corresponding shocks delivered to the wheel and work'because of the inertia of the frame and driving mechanism, and another important object of my invention is to correct this condition by the insertion of resilience in the supportin connection between the hood and frame.

In Figure 2, the parts intended to be optionally the same as in Figure 1 are given corresponding numerals primed and their description, given for Figure l, is not repeated. for Figure 2.

In Figure 2 I provide resilience in the supporting connection between the frame and hood and show this conventionally as a fiat spring 35 of size and resilient characteristics to suit the intended service.

The spring 35 is illustrated as rigidly fastened, as by welding, at one end to the frame 5' and at the other end to the hood'l.

In view of my invention and disclosure, variations and modifications will doubtless become evident to others skilled in the art and I claim all such in so far as they may fall within the reasonable spirit and scope of the invention.

' Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

1. A swing frame grinder having an operating handle, a grinding wheel, a hood carrying the handle and mounting the wheel,-a swing frame supporting the hood in a position longitudinally intermediate the handle and frame and the structure characterized by ahinge between the handle and hood adapting the handle to downward deflection from its position of normal operation and a spring upwardly retracting the handle to its position of normal operation and during grinding resiliently cushioning the handle from vibration of the hood.

2. A swing frame grinder having an operating handle, a grinding wheel, a hood carrying the handle and mounting the wheel, a swing frame supporting the hood in a position longitudinally intermediate the handle and frame and the structure characterized by a hinge between the handle and hood adapting the handle to downward deflection from its position of normal operation and a spring upwardly retracting the handle to its position of normal operation and additionally characterized by a spring connection between the hood and frame whereby during grinding the hood is resiliently cushioned from vibration of the frame.

3. A swing frame grinder having a swing frame, an operating handle, a grinding wheel, a hood mounting the wheel, a hinge between the handle and hood adapting the handle to downward deflection from its position of normal operation and a spring resiliently retracting the handle against normal down-pressure applied by an operator and of resilience to limit the down pressure that an operator may transmit through the handle and hood to the wheel and work.

4. A swing frame grinder having an operating handle, a grinding wheel, a hood supporting the handle and mounting the wheel, a swing-frame supporting the hood and the structure characterized by a hinge between the handle and hood adapting the handle to downward deflection from its position of normal operation and by a latch latching the handle from downward deflection during normal operation and releasing under abnormally high pressure applied to the handle.

5. A swing frame grinder having an operating handle, a grinding wheel, a hood supporting the handle and mounting the wheel, a swing-frame supporting the hood and the structure characterized by a hinge between the handle and hood adapting the handle to downward deflection from its position of normal operation, by a spring upwardly retracting the handle and by a latch latching the handle from downward deflection during normal operation and releasing under abnormally high pressure applied to the handle.

CHARLES E. HITE. 

